1. Field of the Invention
The present invention relates to a method for producing a plant having a high growth rate. More specifically, the present invention relates to proteins, OsHDAC1, OsHDAC2 and OsHDAC3, which function as a histone deacetylase, a gene coding for said proteins, and a method for producing a plant having a high growth rate by expressing said gene in the plant.
2. Description of the Related Art
Acetylation and deacetylation of histone are basic mechanisms to control the transcription of eukaryotic organisms wherein histone acetyltransferases (HATs) loose nucleosome by acetylation of histone to stimulate transcription, and histone deacetylases (HDACs) play a role of inhibiting the transcription through inhibition of the activity of HATs. The HDACs found in mammals can be classified generally into two classes: the HDACs belonging to class I, composed of approximately 400 to 500 amino acids having a homology with RPD3 as histone deacetylase of yeast, and the HDACs belonging to class II, composed of approximately 1000 amino acids having a homology with yeast's HDA1. Up to the present, HDACs have been very extensively studied and are known only in mammals and yeast, whereas plant HDACs have been known only in that they may be related to the failure of phenotypic function in the Arabidopsis and maize plant.
ABA (abscisic acid) is a plant hormone related to various physiological reactions including those against environmental stresses such as seed generation, dormancy or drought, high concentration of salts and cold. It has been known that abscisic acid plays an important role in maintaining the survival of the plant body by inhibiting the germination and growth of seeds and buds when the plant is under unsuitable growth conditions (see, Seo, M. and Koshiba, T., Trends Plant Sci., 7: 41–48, 2002). However, in monocot plants including rice, barley, wheat and maize for food production, it is more important that the productivity be increased by maintaining growth under unsuitable environmental conditions, than the maintenance of survival.
Therefore, there is a continuous need for developing the plant body, which can be maintained at a high growth rate even under stress conditions.
Thus, the present inventors have earnestly and extensively studied to develop a plant body having a high growth rate even under stress conditions. As a result, we have identified that OsHDAC1, among the three kinds of OsHDAC genes isolated from the rice plant, is expressed locally in the whole plant body, and when it is overexpressed, it changes the growth rate and phenotype of the plant and increases the growth of the plant body through increasing its expression even in the presence of ASA which inhibits germination and growth, and thus, completed the present invention.
Ultimately, the main purpose of the present invention is to provide protein OsHDACs that function as a histone deacetylase.
Another purpose of the present invention is to provide a gene OsHDAC coding for said protein.
Further, another purpose of the present invention is to provide a method for producing a plant body having a high growth rate which comprises the step of expressing said OsHDAC genes in the plant body.